Abstract: Objective The aim of the present study was to evaluate the accuracy between the stardard 3-conclusion scale and 5-conclusion scale of footprint examination, and to determine whether the footprint comparison process would benefit from an expanded conclusion scale. Methods Twelve footprint examiners, with an average experience of more than 16 years, were invited to participate in the research and completed 50 footprint pairs using the two conclusion scales respectively. Statistical methods such as signal detection theory were used to compare the differences between conclusion scales and analyzed potential changes in decision thresholds. Results 600 examine opinions were drawn from the two conclusion scales, and there were no significant differences in accuracy, examine time, and comparison difficulty. However, when using the 5-conclusion scale, examiners became more toward risk aversion when making “Identification”, and they tended to convert weaker “Identification and Exclusion” into “Support for Conclusions”. Conclusion There is no statistical difference between the two conclusion scales. The 5-level conclusion scale may be more objective in evaluating the close non-match footprints with challenges, and also provides reference for further quantifying the conclusion scale.

Key words: footprint examination, conclusion scales, accuracy rate, error rate, comparison test

摘要： 目的 旨在分析足迹检验意见的标准3级表述与5级表述的准确性，评估5级表述是否有利于足迹比对过程。方法 邀请12名平均经验在16年以上的足迹鉴定人员，分别使用两种意见表述完成50对足迹检验；采用信号检测论等统计方法比较两种意见表述之间的差异，并分析了意见表述阈值的潜在变化。结果 两种意见表述得出了600个足迹意见，在准确性、检验时间和比对难度上均未产生显著性差异。但是，当使用5级意见时，鉴定人员作出“同一认定”更加趋向风险规避，倾向于将较弱的“认定或否定”转换为“倾向性意见”。结论 两种意见表述在统计学上没有明显差异，5级意见对复杂相似异源足迹的评价可能更为客观，为进一步量化意见表述提供参考。

关键词: 足迹检验, 意见等级, 正确率, 错误率, 比对检验